Method and apparatus for controlling metal separation

Abstract

The invention relates to a method and apparatus for controlling a continuous metal removal in conjunction with a zinc preparation process, in which the metal removal is performed in one or more reactors ( 11 a - c ), in conjunction with the reactor, the redox potential ( 16 a - c ) and the acidity and/or basicity are measured, and based on the measurement results, the process variables ( 17 a - c ) of the metal removal are adjusted towards the desired direction. According to the invention, the redox potential measurements ( 16 a - c ) are performed from the sludge produced in the reactor in conjunction with the outlet pipe of the reactor outside the reactor, and the measuring instrument ( 16 a - c ) is purified at predetermined intervals.

1. A method for controlling a continuous cobalt removal in conjunction with a zinc preparation process, in which the cobalt removal is performed in at least two reactors comprising a first reactor and a second reactor connected in series and having a connecting pipe between the two reactors and an outlet pipe from the second reactor, in conjunction with the two reactors, redox potential and acidity and/or basicity are measured, and process variables of the cobalt removal are adjusted toward a desired direction based on the measurement results, wherein the measurement of the redox potential is performed on a sludge produced in the two reactors and is performed in the connecting pipe and in the outlet pipe, and measurement of the acidity and/or basicity are performed on a reactor solution and are determined by means of a BT value, and a measuring instruments of the redox potential are purified at predetermined intervals, and based on the measurement results, introduction of zinc powder into the cobalt removal reactors is adjusted to provide a BT value of about 1.0 to 3.0. 
     
     
       2. The method as defined in  claim 1 , wherein a solid matter content of the reactor solution is determined and adjusted to be suitable. 
     
     
       3. The method as defined in  claim 2 , wherein based on the measurement results, the redox potential of the sludge, the acidity/basicity of the solution, the solid matter content of the solution and/or the temperature of the reactor are adjusted. 
     
     
       4. The method as defined in  claim 1 , wherein the measuring instrument of acidity and/or basicity is arranged in conjunction with the two reactors. 
     
     
       5. The method as defined in  claim 1 , wherein the measurement of the redox potential is performed using a measurement electrode. 
     
     
       6. The method as defined in  claim 1 , wherein the measuring instrument is regularly washed. 
     
     
       7. The method as defined in  claim 1 , wherein in conjunction with each reactor, measurements are performed that control the adjustment of the desired process variable, for each reactor specifically. 
     
     
       8. The method defined in  claim 1 , wherein the measuring instrument is regularly washed at intervals of 1-2 hours. 
     
     
       9. The method as defined in  claim 1 , wherein the outlet pipe comprises a connecting pipe to a third reactor. 
     
     
       10. An apparatus for controlling a continuous cobalt removal in conjunction with a zinc preparation process, in which the cobalt removal is performed in at least two reactors comprising a first reactor and a second reactor connected in series and having a connecting pipe between the two reactors and an outlet pipe from the second reactor, the apparatus comprising at least one measuring instrument for measuring the redox potential and acidity and/or basicity in conjunction with the at least two reactors, at least one adjustment device for adjusting process variables of the cobalt removal toward a desired direction based on the measurement results, and at least one control device for forwarding the measurement results from the at least one measuring instrument to the at least one adjustment device, wherein the measuring instruments of the redox potential is are arranged in the connecting pipe and in the outlet pipe, and placed in conjunction with a pipe connected to the one or more reactors, via which pipe sludge produced in the one or more reactors flows out, and the apparatus comprises a determination device of BT value for determining the acidity and/or basicity of a reactor solution, and the apparatus comprises purification means for purifying the at least one measuring instrument of the redox potential at predetermined intervals, and based on the measurement results, introduction of zinc powder into the cobalt removal reactors is adjusted to provide a BT value of about 1.0 to 3.0. 
     
     
       11. The apparatus as defined in  claim 10 , wherein the apparatus comprises a feeding device for introducing zinc powder into the one or more reactors, and the feeding device is connected to the at least one adjustment and/or at least one control device. 
     
     
       12. The apparatus as defined in  claim 10 , wherein the measuring instrument of acidity and/or basicity is arranged in conjunction with the two reactors. 
     
     
       13. The apparatus as defined in  claim 10 , wherein the measuring instrument of the redox potential comprises at least two measurement electrodes. 
     
     
       14. The apparatus as defined in  claim 10 , wherein the outlet pipe comprises a connecting pipe to a third reactor.